The FCC’s regulation governing the standards for the permissible amount of radio frequency emission from a cellphone (47 C.F.R. § 1.1310(c)) preempt plaintiff’s state law claims that Apple’s iPhones are unsafe even though they conform to the FCC’s standards. The FCC issued its regulation under the broad authority that Congress conferred on it in the Federal Communications Act of 1934. The FCC’s standards reflect its careful balancing of interests in public safety against public access to cellphone technology. Applying different state standards would reset that balance and essentially make the FCC standards meaningless, disrupting the uniform federal scheme that Congress intended. Congress need not expressly confer preemptive authority on a federal agency; its regulations preempt conflicting state law unless Congress says otherwise. A general savings clause saying that nothing in the Act supersedes state law is not given broad effect when doing so would interfere with the intended scheme of federal regulation.